Lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) are very common findings in aging men and present a considerable health care burden both in terms of morbidity as well as health care resource utilization. Aside from the standard therapy transurethral resection of the prostate (TURP), medical therapies and minimally invasive surgical therapies (MIST) have been developed over the past decade, which are utilized to varying degreed. Fundamentally, information regarding the relative efficacy and safety, as well as tolerability of these procedures in an outpatient setting under local anesthesia, and importantly, durability of the initial results over intermediate follow-up periods is lacking. Further, due to a lack of understanding of the mechanism of action of some of the treatments, there are no known baseline parameters that could be used as predictors of a successful outcome. The MIST Study Group will develop several clinical trial protocols to address these issues over a 5 year time period. A four-arm randomized trial comparing the safety and efficacy of TURP vs TUMT vs TUNA vs ILTT with a 3 year follow-up is proposed enrolling 600 patients with moderate to severe LUTS and BPH at 15 centers as the first study done by the MIST Study Group with the following objectives: (1). Determine the efficacy of three different minimally invasive surgical therapies (MIST: TUMT, TUNA, Interstitial Laser Thermal Therapy) for LUTS and clinical BPH compared with the standard treatment TURP by electrocautery as measured by a standardized symptom severity assessment instrument (2). Determine the safety and tolerability of three different minimally invasive therapies (TUMT, TUNA, Interstitial Laser Thermal Therapy) for LUTS and clinical BPH compared with the standard treatment TURP by electrocautery (3). Determine the rate of retreatment or secondary treatments following the MIST intervention compared with the standard treatment TURP by electrocautery. (4) Determine whether pre-treatment urodynamic status impacts upon the treatment outcome as defined by symptomatic improvement. (5) Determine the relative efficacy as measured by maximum urinary flow rate, post-void residual urine volume, prostate volume changes, and serum PSA changes. During the course of this first trial, the MIST Study Group will meet regularly to develop a 2nd, 3rd and subsequent trials. The nature of these additional trials will depend on a needs assessment, the development of new MIST interventions, the findings obtained in the first trial and other factors. The MIST Study Group will be a blueprint for a technology assessment group applicable to other areas of urology and other medical or surgical subspecialties.